Patent GB-290729-A (GB)
Title: An improved hardness testing device
IPC: G01N3/42
Filed: 1927-02-18
Abstract: 290,729. Wilson, C. H. Feb. 18, 1927. Testing harness of materials. - Comprises a machine having the general automatic character of that described in Specification 277,517 but adapted to deal with heavy or large objects. A wide flat base 10 supported by legs 11 is provided with ribs 13 in the ends of which are located sockets for balls 22. The piece to be treated is placed either directly on the balls 22 or on a plate 25 resting on them, and the operator starts the apparatus by lowering a lever 111 to release a stop pin 110 on a crank wheel 100. This wheel is turned by a spring motor and has a stop pin 110 which when released from the shoulder 114 on the lever 111 allows the wheel to give a quarter turn bringing the stop pin 110 to engage under the pivoted armature 117 of an electromagnet 135. During this movement, the link 102 is actuated to move the clutch collar 103, splined to a shaft 83, into engagement with the gear 90 in mesh with a gear 81 continuously driven from a power driven pulley 82. The shaft 83 is thus rotated, and through worm gear 86, 87 drives a shaft 75 splined on which is a gear 76 in gear with a wheel 77 which rotates a transverse shaft 60 which drives a transverse shaft 59 and two short transverse shafts 61 carried in bearings in a bridge piece 30. The shafts 61 and 59, through worm gear, operate nuts engaging vertical screws 27, 28 so that the bridge piece is raised or lowered on the screws. In the first movement of the machine, the bridge piece is lowered until the testing point 41 engages the work. An extension 120 of the part 41 raises the pivoted minor load lever 122 until the contact 128 engages the contact 129 to close the circuit of a relav 135 whereupon the armature 117 is withdrawn from the pin 110 and the crank wheel 100 turns until the pin engages the upper plate 142 of a double pawl. The indicator 125 is zeroized at this stage. During this movement of the machine, the clutch. sleeve 103 is thrown into neutral position and a clutch collar 148 is engaged with the clutch teeth 153 by movement of a lever 146 due to the engagement of the end 147 by a pin 145 on the crank wheel. The drive from the gear 81 through the wheel 154 and worm gear 159, 160 now rotates the splined shaft 165 and through mitre wheels 170, 171 and a horizontal shaft 172 rotates a shaft 175 on which is the cam 178 which lowers the major load lever 180 by engagement with a pin 181, and applies pressure to the point 41 to penetrate the specimen. The continued revolution of the cam 178 raises the lever 180 and releases the pressure, the hardness number being read off on the indicator 125. During this movement of the major load lever, a lower cam 192 has depressed a pin 191 and through a linkage 190 raised the pawl 142 so that the pin 110 engages the pawl 143. At the completion of the movement, the pin 191 drops and the pin 110 is released, the crank wheel rotating until the pin 110 engages the end 198 of the reverse pawl 197. This movement disengages the clutch collar 148 and engages the sleeve 103 with the pinion 91, rotating the shaft 83 in the opposite direction to raise the bridge until the rod 210 closes the switch 205 and the magnet 200 is energized to attract the armature 197 and release the pin 110. The wheel 100 now makes a last quarter turn until the pin 110 comes to rest against the shoulder 114 of the release lever 111 ready to go through the same cycle again. The driving spring ior the wheel 100 is wound up one revolution for every revolution of the crank wheel by a chain drive from the lower shaft 161.